The present invention relates to a water treatment method and an apparatus therefor which are suitable for use where treatment objective water is treated in purification to produce super pure water, potable water and the like, or for use where seawater is treated in desalination.
It has been known that, if ozone is utilized to purify treatment objective water, a strong oxidation and sterilization action of the ozone makes it possible to remove contamination due to, particularly, organic substances. For this end or purpose, however, it is required that a plenty of ozone gases high in concentration is mixed with the treatment objective water. Since the ozone is apt to be immediately changed to oxygen. In addition, since a normally high water pressure is applied to a flow system which causes the treatment objective water to flow, it is extremely difficult to practically mix the plenty of ozone gases with and into the treatment objective water. Further, in spite of the fact that uses of the treatment objective water are for industry and for agriculture, it is naturally required to treat in purification a plenty of water like several tons or several ten tons per hour. However, an ozone supply apparatus which satisfies such condition is close to none at all, in the extent or range as far as the inventor of the present application knows.
In view of the above, the inventor of the present application has previously proposed an apparatus which is capable of mixing a plenty of ozone gases high in concentration into treatment objective water, on the assumption that a plenty of treatment objective water is purified (for example, reference should be made to Japanese Patent Laid-Open No. SHO 63-200891). Further, the inventor of the present application has proposed a water treatment apparatus which utilizes the above-described apparatus (for example, reference should be made to Japanese Patent Publication No. HEI 3-72359).
In a process to pursue such a technique of purifying the water, it has been possible to obtain knowledge that the technique developed by the inventor of the present application is extremely effective in obtaining super pure water and potable water, and the technique is useful also for desalination of the seawater.
Generally, in order to obtain super pure water, waterwork water, underground water, industrial water and the like are used as raw water. As will be known well, however, various impurities are contained in the water. Specifically, contained In the water are rubbish or refuse and other suspendible particles, fine particles of a silt-like material or the like, microorganisms such as bacteria and the like, and a colloidal material, as an "insoluble material", for example, and organic substances such as ion, protein and the like, soluble gasses such as oxygen/carbon dioxide gases and the like, as a "soluble material".
For the reason discussed above, in order to obtain super pure water, it is necessary to efficiently remove such impurities. Particularly, the pure water for semiconductors contains elements harmful for the semiconductors, and dislikes or hates bacteria (raw fingi or viable cells) being grown. Thus, it is required to completely remove the bacteria.